docs: def sympy_to_scipy(func, vars, params):
      """
      Convert a symbolic expression to one scipy digs. Not used by ``symfit`` any more.
  
      :param func: sympy expression
      :param vars: variables
      :param params: parameters
      :return: Scipy-style function to be used for numerical evaluation of the model.
      """
      lambda_func = sympy_to_py(func, vars, params)
      def f(x, p):
          """
          Scipy style function.
  
          :param x: list of arrays, NxM
          :param p: tuple of parameter values.
          """
          x = np.atleast_2d(x)
          y = [x[i] for i in range(len(x))] if len(x[0]) else []
          try:
              ans = lambda_func(*(y + list(p)))
          except TypeError:
              # Possibly this is a constant function in which case it only has Parameters.
              ans = lambda_func(*list(p))# * np.ones(x_shape)
          return ans
  
      return f